If it works out that way. The primary reason the Army is changing to the 6.8 is to increase the effective range of the basic rifleman. They don’t necessarily have to make hits with a very shot. If they pin down the enemy with fire they call in a air strike.
The issue is the same thing we have been discussing regarding using a pistol cartridge vs a rifle cartridge. If your opponents weapons out range you than you are in a world of shit.
Any rifle cartridge will out range a 9mm. It’s only a matter of picking the platform to be used.